Calcium-induced Ca2+ release from sarcoplasmic reticulum of pigs susceptible to malignant hyperthermia The effects of halothane and dantrolene

AbstractCalcium-induced calcium release and halothane-induced calcium release from pig sarcoplasmic reticulum (SR) were studied. The SR prepared from pig susceptible to malignant hyperthermia (MH) was shown to release calcium at a much lower level of calcium content than in normal pig SR. The concentration above which halothane can release calcium is 40 μM for both MH-SR and normal SR, although the latter required a high calcium content to demonstrate the calcium release. Dantrolene was shown to inhibit the halothane-induced calcium release. Results suggests that SR plays an importnat role in pathogenesis of MH

Contracture Responses and Energy Stores in Quadriceps Muscle from Humans Age 7-82 Years

Thirty-three patients, with normal muscle function, ranging in age from 7-82 years and undergoing elective orthopedic surgery agreed to quadriceps muscle biopsy. At all ages, contracture responses to caffeine or to 2% halothane and caffeine at 37°C were similar. The threshold to caffeine was 2-4 mM, and the plateau of the dose-response curve was above 32 mM; the threshold to halothane-caffeine was 0.25-0.5 mM, and the plateau 16 mM. Contractures were not observed when the muscle bundles were exposed solely to 2% halothane. Incubation of muscle bundles with 2% halothane for 45 min at 37°C resulted in minimal depletion of energy stores. The ratio of the halothane-exposed concentration to that of the non- halothane level was, for adenosine triphosphate and creatine phosphate, respectively, about 1.0, and 0.9. Examination of contracture responses did not reveal changes with maturation or aging, and do not explain age-related changes in muscle function

Malignant hyperthermia — Human stress triggering

Letter to the Editor concerns the question of a discussion of awake porcine malignant hyperthermia that erroneously omits the awake human stress reaction of malignant hyperthermia

Cholinesterase inhibition by potato glycoalkaloids slows mivacurium metabolism. Anesthesiology 2000

Background: The duration of action for many pharmaceutical agents is dependent on their breakdown by endogenous hydrolytic enzymes. Dietary factors that interact with these enzyme systems may alter drug efficacy and time course. Cholinesterases such as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) hydrolyze and inactivate several anesthetic drugs, including cocaine, heroin, esmolol, local ester anesthetics, and neuromuscular blocking drugs. Natural glycoalkaloid toxins produced by plants of the family Solanaceae, which includes potatoes and tomatoes, inhibit both AChE and BuChE. Here the authors assess the extent to which two solana